Electric switch.



No. 783,997. PATENTED FEB. 28, 1905. E. R. DOUGLAS.

ELECTRIC SWITCH.

APPLICATION FILED NOV. 30, 1903.

UNITED STATES Patented February 28, 19053,

PATENT 'OFFICEo EDVIN RUST DOUGLAS, OF EAST ORANGE, NET JERSEY, ASSIGNOR TO OROOKER-l/VHEELER COMPANY, OF AMPERE, NElV JERSEY, -A CORPO- RATION OF NEV JERSEY.

ELECTRIC SWITCH.

SPECIFICATION forming part of Letter; Patent No. 783,997, dated February 28, 1905.

vApplication filed November 30, 1903. Serial No. 183,182.

To all whom/ji; ntf/U con/cern.'

Be it known that 1, EDWIN RUST DOUGLAS, a citizen of the United States of America, and a resident of East Orange, county of Essex, and State of New Jersey, have invented certain new and useful Improvements in Electric Switches, of which the following is a specilication.

This invention relates to an improved form ro of construction for an electric-switch cylinder whereby sectional contact-rings are accurately and securely positioned on the convex surface of a cylindrical core of insulating material by reason of the provision of circumferential I 5 tongues and grooves and longitudinal keys and keyways between the cylindrical core and each section of a contact-ring.

The sections of the contact-rings for eli'ecting multiple-voltage changes and the sections 2o of the contact-rings for effecting reversals of connections have substantial forms which are well suited to attachment t0 the cylindrical core; and the invention is such as to permit the adoption of an interchangeable method of 2 5 construction by which the sections can be formed and iinished before assenibling` on the core and sections of contact-rings can be conveniently removed without having to detach or disturb other sections, thus aliording a con- 3o struction wherein the sections with contacts which are liable to wear or injury can be readily removed and replaced by new sections of the contact-rings which are interchangeable with the sections that are removed.

3 5 This invention'has been designed with reference to its applicability in a switch to be used in connection with the system of electricmotor control set forth inUnited States Letters Patent No. 735,352, granted August A,

1903, on an application by Gane S. Dunn, and United States Letters Patent No. 736,587, granted August 18, 1903, on an application by Grano S. Dunn and myself. ltsapplicability,

however, is quite general and is particularly important in controllers which make a large number of different electrical combinations or have a large number of circuit positions or steps, thereby requiring a cylinder of considerable circumference in comparison with the general size and weight of the contactrings.

In the accompanyingl sheet of drawings, which form a part of this application, Figure 1 is an elevation of a switch embodying my invention, the inclosing casing being broken away. Fig. 2 is a perspective view of a key. Fig. 3 is an elevation of the core. Fig. 4 is a top view of the core. Fig. 5 is a perspective view of one section of the contact-rings. Fig. (5 is adevelopment of the switch-cylinder, showing the developed surface of the core and the contact-rings and electrical connections.

The switch herein illustrated is provided with contacts for effecting the shifting of the connection of the armature and series-field leads of a compound-wound motor M between four conductors a 7; c (l, which have different potentials maintained between them,and hence are the supply-conductors of a multiple-voltage system. The switch is also provided with contacts for effecting' changes in the shunt-field winding of the motor by introducing resistance into the field-circuit in the manner and in the sequence set forth in the second Letters Patent abovereferred to. The switch also is arranged to supply current to the arniai'ure at four of the potentials in reverse directions for reverse movement, but without the lieldvariation feature.

Then the switch is operated, the armature SO and series field-circuit is from the contact-iinger on one or the other of the supply-conductors a c, according to the operated position of the switch as set forth in the above-nientioned patents, to one of the two multiple-vol- S5 tage contact-rings, which in the form herein disclosed is in two sections e e. Thence 'from the contacts of this ring the circuit is to a multiple-voltage contact-linger of ashort connectionf; thence through a contact-linger on the other end of the short connection to one of the two reversing contact-rings, which is also in two sections ry y', to one or the other of two contact-iingers at the ends of the motorarmature leads, accordingly as the contacts at the right or the left of the line of contactlingers are brought under the fingers; thence through the connected leads and the armature to the other lead and contact-finger; thence from this contact-finger to the other reversing' contact-ring, also in two sections /i It', to a contact-finger' on the end of a lead from the i series field; thence from this contact-finger and lead through the series field-coils and the other lead to its multiple-voltage contact-iinger on the end of this lead, and thence from this contact-finger to the other multiple-voltage contact-ring, also in two sections to a supply-conductor contact-finger on one or the other of the supply-conductors I) c (Z, the latter connection to the leads being as set forth in the above-mentioned patents. The two multiple-voltage contact-rings effect connections by which one of several voltages is supplied over the circuits and connections above traced between the two above-mentioned multiple-voltage contact-fingers, and these fingers are termed multiple-voltage contact-fingers to distinguish them from the contact-fingers which are terminals of the supply-conductors, each of which is maintained at a fixed potential.

The shunt-field is varied by contacts on a field-varying contact-ring consisting of two sectionsZ Z. The connections are as set forth in the second of the above-mentioned patents when the contacts at the left of the line of contact-fingers in Fig. 6 are brought under the fingers, and provision is thereby7 made for twenty-three different speeds. The contacts at the right, which are for reverse movement, are not combined with field-variation contacts, and provision is only made for four positions at the first four voltages at full-field strength, since reverse movement is not so important, and provision for as many speeds and positions with the motor reversed as with the motor running forward would unduly enlarge the switch.

The contact-rings are mounted on a core of insulating material m, which is circumferentiall y grooved at o and longitudinally grooved at y). There is a circumferential groove for each set of contacts and two longitudinal grooves on opposite sides of the core. Each of the sets of contacts of each ring almost completely surrounds the switch, and cach ring is divided into two sections, and each section has a tongue n, preferably integral with the section, which projects inwardly from its con- :ave side and engages an underlying circumferential groove. As the function of each contact-ring is only to bridge contact-lingers on the same element of the cylinder and there is no electrical reason for continuity circumferentially, each ring is divided or split into two sections, and each section occupies approximately a semicircle or less, so that it can be fitted onto the circum ferentially-grooved core.

A transverse keyway f] is formed in the conlave surface of each section of each of the contact rings and is eut through the tongue formed thereon. This keyway overlies one or the other of the longitudinal grooves in the core. A key r, which is of liber or other suitable insulating material, secures the rings on the core against circumferential displacement. Two longitudinal grooves and keys are su llicient, since each section approximately covers a semicircle, and the two longitudinal grooves can be readily located so that each of the sections will overlie one or the other of the grooves. ln addition to the tongues and keys to prevent longitudinal and circumferential displacement of the sectional contact-rings screws s pass through the sections into the core and secure the sections to the surface of the core.

The two sets of multiple-voltage contactrings each carry four circumferential rows of contacts. Three of the rows con tact with contact-fingers of the supply-conductors` and these rows each carry contacts at but a few points of the circun'iference of the switch. The other row contacts with a multiple-voltage eontact-finger and has contacts at each operated position of the switch throughout the circumference. This ring I preferably make one of the intermediate rows and locate the tongue under this row in each contactring section,`since with the rib near the medial line of the section the section will have a more compact and solid construction and can have a more stable seat on the core. The points of the circumference where the rings are divided into sections are deterl'nined b v structural reasons, since the electrical separa.- tion of the parts of the rings is immaterial, it being' mainly necessary that the two points of division of any one ring shall be about opposite, so that neither section will embrace more than a semicircumference, or but slightly more, in order that it may be removed without having to take oli other rings and slip it off the end.

Two rings are required for effecting the reversal of connections to the armatnre-leznls in passing' the ofi' position, and each ring has two parallel rows of contacts on both sides of the off position. One of the sections, /1, is formed in two branches lying on opposite sides of the ofi' position, one of these branches being forked. Each of the two forks v' carries a row of contacts, and the two branches of theI semieircular contact-ring section, which is forked, lie on opposite. sides of the oli position. By this construction it will be seen that electrical connection is provided between the two separated rows of contacts on the forks. One of the sections, g, of the other ring also has two branches, one of which lies between the forks of the other ring and carries contacts for the reverse operated positions and the other branch of which carries contacts for some of the forward operated positions of the switch.

IOO

lt is not essential to all objects of my invention that the circumferential tongue be integral with the section which it serves to position on the core. For this purpose it acts as a key and may or may not be integral with either part.

That I claim as new, and desire to secure by Letters Patent of the United States, is

1. In an electric switch, the combination of a cylindrical core of insulating material, contact-rings consisting oi' sections, a circumferential tongue between each contact-ring' section and the core, and means for securing each of the sections to the surface of the core, substanti-ally as described. c

2. ln an electric switch, the combination ot' a cylindrical core of insulating material, contact-rings consisting of sections, a circumferential tongue between each contact-ring section and the core and integral with one of the parts, and means for securing each of the sections to the surface of the core', substantially as described.

3. ln an electric switch, the combination ot' a circumferentially-grooved cylindrical core oli insulating' material, contact-rings consisting of sections, each section being provided with a tongue fitting into a circumferential groove ol" the core, and means Vtor securing' each of the sections to the surface of the core, substantially as described.

4. In an electric switch, the combination of a cylindrical core of insulating material, contact-rings consisting' of sections, a circumferential tongue between each contact-ring section and the core, a key parallel with the axis of the core between each contact-ring section and the core, and means for securing each ol the sections to the surface of the'core, sub* stantially as described.

5. In an electric switch, the combination ot' a circumferentiall y and longitudinally grooved cylindrical core of insulating material, contact-rings consisting of sections, each section being formed with a transverse keyway and with a tongue iitting into a circumferential groove of the core, keys ot' insulating material titted into the longitudinal grooves of the core and the transverse keyways of the sections, and means for securing the sections to the surface of the core, substantially as described.

Signed by me at East Orange, New Jersey, this 27th day of November, 1903.

EDW'IN RUST DOUGLAS.

'Vitnesses:

SAMUEL BALCH, GEO. lV. ownl-z. 

